I assume this behaviour is a bug, so I want to share it here. Perhaps there is even a solution?

I go to sleep or hibernate, I come back and the network applet tells me, that I am still connected. Since it thinks I am still connected, it does not reconnect me. Though the internet is not working. The only thing I can do is close the connection manually and reconnect manually. Waiting does not help.

It would be helpful if it would automatically reconnect after sleep/hibernate.

In your case, like mine, the driver is "iwlwifi". I have to do this for two laptops.
Possibly we could add the config file with an assortment of module names to the default install or to a MX config package, since several users have reported the same problem.